import AuthCipher from "./authCipher";
import MODES from "./modes";
import StreamCipher from "./streamCipher";
import Transform from "../cipher-base";
import * as aes from "./aes";
import ebtk from "../evp_bytestokey";
import { inherits as inherits$0 } from "util";
var inherits = { inherits: inherits$0 }.inherits;
function Decipher(mode, key, iv) {
    Transform.call(this);
    this._cache = new Splitter();
    this._last = void 0;
    this._cipher = new aes.AES(key);
    this._prev = Buffer.from(iv);
    this._mode = mode;
    this._autopadding = true;
}
inherits(Decipher, Transform);
Decipher.prototype._update = function (data) {
    this._cache.add(data);
    var chunk;
    var thing;
    var out = [];
    while ((chunk = this._cache.get(this._autopadding))) {
        thing = this._mode.decrypt(this, chunk);
        out.push(thing);
    }
    return Buffer.concat(out);
};
Decipher.prototype._final = function () {
    var chunk = this._cache.flush();
    if (this._autopadding) {
        return unpad(this._mode.decrypt(this, chunk));
    }
    else if (chunk) {
        throw new Error('data not multiple of block length');
    }
};
Decipher.prototype.setAutoPadding = function (setTo) {
    this._autopadding = !!setTo;
    return this;
};
function Splitter() {
    this.cache = Buffer.allocUnsafe(0);
}
Splitter.prototype.add = function (data) {
    this.cache = Buffer.concat([this.cache, data]);
};
Splitter.prototype.get = function (autoPadding) {
    var out;
    if (autoPadding) {
        if (this.cache.length > 16) {
            out = this.cache.slice(0, 16);
            this.cache = this.cache.slice(16);
            return out;
        }
    }
    else {
        if (this.cache.length >= 16) {
            out = this.cache.slice(0, 16);
            this.cache = this.cache.slice(16);
            return out;
        }
    }
    return null;
};
Splitter.prototype.flush = function () {
    if (this.cache.length)
        return this.cache;
};
function unpad(last) {
    var padded = last[15];
    if (padded < 1 || padded > 16) {
        throw new Error('unable to decrypt data');
    }
    var i = -1;
    while (++i < padded) {
        if (last[(i + (16 - padded))] !== padded) {
            throw new Error('unable to decrypt data');
        }
    }
    if (padded === 16)
        return;
    return last.slice(0, 16 - padded);
}
function createDecipheriv(suite, password, iv) {
    var config = MODES[suite.toLowerCase()];
    if (!config)
        throw new TypeError('invalid suite type');
    if (typeof iv === 'string')
        iv = Buffer.from(iv);
    if (config.mode !== 'GCM' && iv.length !== config.iv)
        throw new TypeError('invalid iv length ' + iv.length);
    if (typeof password === 'string')
        password = Buffer.from(password);
    if (password.length !== config.key / 8)
        throw new TypeError('invalid key length ' + password.length);
    if (config.type === 'stream') {
        return new StreamCipher(config.module, password, iv, true);
    }
    else if (config.type === 'auth') {
        return new AuthCipher(config.module, password, iv, true);
    }
    return new Decipher(config.module, password, iv);
}
function createDecipher(suite, password) {
    var config = MODES[suite.toLowerCase()];
    if (!config)
        throw new TypeError('invalid suite type');
    var keys = ebtk(password, false, config.key, config.iv);
    return createDecipheriv(suite, keys.key, keys.iv);
}
export { createDecipher };
export { createDecipheriv };
